Wetting and emulsifying agent



Patented May 2, 1944 WETTING AND EMULSIFYING AGENT Kenneth M. Gaver, Columbus, Ohio, assignor to The Komel Corporation, Dayton, Ohio, a corporation of Delaware No Drawing. Original application February 15,

1941, Serial No. 379,126. Divided and this application October 18, 1941, Serial No. 415,641

9 Claims.

This invention relates to wetting and emulsify ing agent and is a division of my copending application Serial No. 379,126, filed February 15, 1941.

More particularly, this invention-deals with an improved amylaceous composition which is useful as a wetting and emulsifying agent in forming emulsions and in compounding various compositions wherein it is required to disperse solid or liquid particles in a carrier. According to my invention, I provide a wetting and emulsifying agent which substantially reduces the surface tension of aqueous solutions and is useful in forming coating and impregnating compositions for treating fibrous materials including paper, cloth, leather and the like.

Furthermore, I provide an amylaceous product comprising 'a colloidal dispersion of alkali metal starchate in water which possesses greatly superior wetting and emulsifying properties as com pared with the conventional starch compositions. This product is a metallic hydrophilic colloid which is colloidally soluble in water and adapted for incorporating with pigments, oils, resins, waxes and the like wherein to function as a protective colloid to assist in forming dispersions of these substances in different vehicles. This product forms low viscosity colloidal solutions or dispersions in water and has marked wetting and emulsifying properties.

My invention is based upon the discovery that an improved composition or emulsifying product is obtained by reacting starch with alcohol soluble hydroxides, such as sodium, potassium, and the like, under conditions such that the metallic starch alcoholate is produced wherein the alkali metal is attached through an oxygen atom to a carbon atom in the 2 position in the complex u-glucopyranose or a-glycopyranose residue. This alkali metal starch alcoholate compound, when dissolved in water, forms a limpid solution which provides an improved emulsifying vehicle. This composition may be used for the emulsifying of substances, such as oil, resins, waxes and synthetic substances wherein it is desired to uniformly disperse the water insoluble particles throughout an aqueous vehicle. My composition may also be utilized as a wetting agent for dispersing pigment particles in the preparation of paints, lacquers and enamels. My emulsifying and wetting product is entirely different from ordinary starch in that my product is readily dispersible in water and yields a filterable low viscosity colloidal solution.

The method of making the alkali metal starchate which is used in forming my improved wetting and emulsifying agent may comprise reacting 417 1 pounds of flake caustic soda or caustic potash in approximately 500 gallons of industrial ethyl alcohol. The mixture is allowed to stand to precipitate the carbonate impurities present which are removed by filtration. I

Approximately 500 pounds of dry starch (i. e. potato starch) is introduced into the alcoholic NaOH solution and the whole mixture refluxed for two hours below 98 degrees C., while being vigorously stirred. The product is then filtered and washed free of alkali with ethyl alcohol and the filter product consisting of sodium starchate is dried below 78 degrees C. in a vacuum oven equipped with means for preventing entry of carbon dioxide and means for recovery of the alcohol.

The dry product is then ground, screened and packed in substantially airtight containers. This process gives a yield of about 94.4% to 99.9% in case of potato starches and 79-82% in case of rice starch.

The sodium starchate compound formed as described is readily soluble in water with spontaneous hydrolysis, whereas the original starch is insoluble.

In producing the sodium starchate, other sources of starch may beemployed such as that derived from corn, wheat, potatoes, sago, arrowroot, cassava, etc.

Further details regarding metallic starchates,

and the method for their preparation are given in my copending application Serial No. 357,995, filed September 23, 1940.

The sodium starchate made according to the above is then dissolved in water to form an aqueous dispersion. This forms a product which possesses a very low viscosity as compared with an ordinary solution of starch in sodium hydroxide. Furthermore, sodium hydroxide starch addition products, as have heretofore been made, do not possess the property of lowering the surface tension of water as low as with the use of the sodium starchate product made as described in the fore going. This formation of aqueous solutions of sodium starchate which possess a high filterability and emulsifying properties is unexpected with the increased quantities of combined sodium hydroxide. Further, this is in direct contrast to conventional solutions of starch and alkali.

The following examples illustrate the various uses to which my new Wetting and emulsifying agent can be utilized:

EXAMPLE I An oil in water emulsion of mineral oil may be' made by dispersing the oil in about a 30% aqueous solution of sodium starchate. Higher concentrations of starchate solutions, however,

may be utilized if desired.- The starchate emulsifying agent may be conveniently made up as follows: 1

Emulsijying agent A 50 parts by weight of sodium starchate is dissolved in from 75 to 100 parts by weight of water. The water may be heated or used cold and the sodium starchate gradually stirredinto the water to form a colloidal dispersion having a. syrupy consistency. If desired, the sodium starchate may be introduced as a powder into the mixture but I prefer to use an aqueous solution of the sodium starchate.

EXAMPLE II be utilized as a waterproof wax composition.

Further, other waxes such as used for making floor waxing compositions and the like may be substituted for paraffin wax.

A liquid polishing wax can be made by forming an emulsion of carnauba wax in a 10% solution of sodium starchate. This forms an aqueous wax dispersion which both cleans and waxes surfaces simultaneously when applied thereto.

EXAMPLE III In the preparation of emulsion-type inks theoil, pigments, modifying agents and water are emulsified by incorporating sodium starchate solution A as an emulsifying agent up to about a solution. In this type of inks, water is employed as the exterior phase and the interior phase consists of the oily substances. The use of sodium starchate solution as an emulsifying agent provides emulsions of improved stability and due to the process of making sodium starchate, the sac around the starch granule is not destroyed and the introduction of the sodium molecule into the starch granules produces a sodium starchate particle which adsorbs the oil particles onto its surface and when dispersed in water the starchate granules rupture spontaneously and uniformly distribute the oil particles throughout the vehicle fo'rming a smooth stable emulsion.

In the preparation of the emulsion-type inks, the pigment particles, such as carbon black and the like which are used, may be first admixed with sodium starchate, either dry particles or in aqueous dispersion, to coat the particles of pigment and function as a surface-active agent to assist in dispersing the pigment particles in the emulsion.

' EXAMPLE IV As an example of an intaglio ink made utilizing my improved emulsifying agent, 15-20 parts by weight of asphalt, such as gilsonite, or equivalent bituminous substance is dissolved in 40-60 parts by weight of petroleum hydrocarbon solvent and emulsified in about from 30-40 parts by weight of water by adding from 5-10 parts by weight of sodium starchate solution emulsifying agent A. This produces a smooth umform emulsion which can be employed for in- .taglio printing. The sodium starchate may be EXAMPLE V In compounding paints, enamels, and the like, wherein pigment particles are to be thoroughly dispersed in an oil vehicle, such as varnish, the pigment may be emulsified with the varnish by using sodium starchate solution A as a wetting agent.

The pigment particles are first thoroughly admixed with suilicient sodium starchate solution to coat the particles and thereafter the coated particles are emulsified with the varnish. To remove the water in order to form an oil-pigment paste, the emulsion is 'broken by the addition of acid or water soluble acid salts and the water separated from the mass by filtration or decanting. In this way, a dispersion of the pigment particles in the oil vehicle is effected without grinding the pigment in the oil, which has been the common practice in the preparation of paints and pigment pastes.

The foregoing examples illustrate some of the different uses to which my new emulsifying agent is adapted, but it will be appreciated that my sodium starchate emulsifying agent is applica ble to other uses for which dispersing and emulsifying agents are employed. The sodium starchate emulsifying agent of this invention has improved wetting and dispersing properties due to the chemically combined alkali metal in the starch molecule. The sodium starchate particles retain the starch granules and produce a product which when brought in contact with water spontaneously ruptures due to the activity of the alkali metal ion, particularly sodium. By combining the active sodium ion with the well known colloidal dispersing properties of starch I have produced a greatly superior wetting and emulsifying agent which can be used either in the powdered form or in a colloidal aqueous solution. The dispersion of pigments, resins, oil, and the like may be effected, for example, by mixing or grinding the insoluble or difilcultly soluble substances with a dispersing agent in the presence of water or by forming an admixture wherein the particles are precipitated in the presence of the dispersing agent producing a paste or liquid product wherein the solid or oil particles are thoroughly dispersed in the vehicle forming a smooth homogeneous product.

This application deals specifically with the use of the wetting and emulsifying agent of my invention in preparing suspensions of pigment in oil, as, for instance, those for use in formulating protective and decorative coatings. Its use in emulsions of oil and water is covered by my copending application Serial No. 379,126, filed Febripry 15, 1941. Furthermore, its use in preparing emulsions of wax and water is covered 'sions.

in my copending application Serial No. 415,640, filed coincident herewith.

It will be understood that the particular proportions set forth in the foregoing examples are merely typical and that my invention covers broadly the preparation of emulsions, dispersions and similar compositions wherein my alkali metal amylaceous wetting and emulsifying agent is utilized for forming uniform homogeneous disper- Further, varying proportions of ingredients may be employed depending upon the type of carrier" and the kind of product desired.

It will be understood that my invention is adapted for widely different embodiments wherein wetting and emulsifying agents are utilized. Furthermore, while I have herein described certain specific embodiments of my invention, it is not intended that it be limited to or circumscribed by the specific details of procedure and proportions indicated inasmuch as modifications may be required to produce the desired results under conditions differing from those herein considered without departing from the spirit of my invention and the scope of the appended claims.

I claim:

1. A new composition of matter including oil and dispersed pigment emulsified with an alkali metal starchate.

2. A new composition of matter including oil and pigment emulsified with a product comprising an aqueous colloidal suspension of sodium starchate.

3. A. pigment oil paste comprising oil and dispersed pigment wherein the pigment particles are coated with a wetting agent consisting of an alkali metal starchate.

4. A paint emulsion comprising varnish emulsified with an aqueous solution of sodium starchate and having pigment dispersed therein.

5. An emulsion-type ink composition comprising oil, pigment and water emulsified by incorporating an aqueous colloidal suspension of sodium starchate.

6. A new composition of matter comprising pigment dispersed in oil wherein the pigment particles are coated with sodium starchate de posited from an aqueous colloidal suspension thereof.

-7. The method of forming pigment dispersions in liquid vehicles comprising mixing the pigment with an aqueous colloidal suspension of sodium starchate as a wetting agent whereby said particles are coated with said sodium starchate and thereafter thoroughly mixing said coated pigment particles with said liquid vehicle whereby there is produced a liquid or paste" wherein the pigment particles are uniformly dispersed throughout the liquid. 

